JP7027708B2 - Battery module and battery pack - Google Patents

Description

The present invention relates to a battery module and a battery pack.

Patent Document 1 describes, for example, a battery module mounted on an electric vehicle or the like. This battery module includes an assembled battery in which a plurality of battery cells are arranged and assembled, a cooling plate for cooling the assembled battery, a heat conductive sheet interposed between the assembled battery and the cooling plate, and a battery adjacent to each other. It is equipped with a separator that insulates the cell. The separator is formed with a notch in which the battery cell is exposed, and the heat transfer sheet is in contact with the battery cell through the notch.

Japanese Unexamined Patent Publication No. 2011-171029

The battery module described in Patent Document 1 has a structure in which a heat transfer sheet is brought into contact with a portion exposed from a notch portion of the battery cell in order to improve heat dissipation of the battery cell. However, in such a structure, it is difficult to bring the heat transfer sheet into contact with the entire surface of the portion exposed from the notched portion of the battery cell. Therefore, in the notch portion, a portion where the battery cell is exposed without being covered with the heat transfer sheet is formed. Therefore, there is a concern that the reliability of the insulation between the battery cell and other components for cooling the battery cell (for example, a housing for accommodating the battery module) may decrease.

An object of the present invention is to provide a battery module and a battery pack capable of increasing the reliability of insulation between a battery cell and a housing while ensuring heat dissipation of the battery cell.

The battery module according to one embodiment of the present invention is a battery module having an array in which a plurality of battery cells held by a cell holder are arranged in a predetermined direction and is fixed to a fixed surface in a housing. A holding portion including a partition wall for holding a surface orthogonal to the arrangement direction in the battery cell, and a side wall provided on one edge of the partition wall and facing the fixed surface and holding the side surface of the battery cell. The side wall has an exposed portion that exposes a part of the side surface of the battery cell, and a part of the exposed side surface in the exposed portion has an insulating property between the side surface and the fixed surface. A coefficient that depends on the degree of contamination of the gas in the space between the side surface and the fixed surface defined by the exposed portion when the heat transfer member that can transfer heat is fixed and the cell holder is fixed to the fixed surface. Is A, the coefficient depending on the voltage difference between the battery cell and the housing is V, the coefficient depending on the temperature in the space is T, and the coefficient depending on the pressure pressure in the space is P, the thickness of the side wall. Is an insulation distance L or more and 2 mm or less, which is proportional to the value calculated by A × V × T / P.

In the above battery module, a heat transfer member having insulating properties and capable of transferring heat is fixed to a part of the exposed side surface in the exposed portion. As a result, the heat generated in the battery cell is efficiently transferred to the housing via the heat transfer member, so that the heat dissipation of the battery cell can be ensured. Further, in the above battery module, the thickness of the side wall of the cell holder is the insulation distance L or more. As a result, a distance of an insulation distance L or more is secured between the side surface of the battery cell and the fixed surface of the housing. Therefore, it is possible to improve the reliability of the insulation between the battery cell and the housing even in the portion of one side surface exposed from the exposed portion where the heat transfer member is not in contact. Further, by reducing the thickness of the side wall to 2 mm or less, the thickness of the side wall can be reduced. As a result, when the battery module is fixed to the fixed surface, the thickness of the heat transfer member arranged between the side surface and the fixed surface is also 2 mm or less. As described above, since the thickness of the heat transfer member is reduced, the heat generated in the battery cell can be efficiently transferred to the housing. Therefore, it is possible to improve the heat dissipation of the battery cell.

In one embodiment, the thickness of the side wall may be 1 mm or more. By setting the thickness of the side wall to 1 mm or more, the distance between the side surface of the battery cell and the fixed surface of the housing can be set to the insulation distance L or more. Therefore, it is possible to improve the reliability of the insulation between the battery cell and the housing even in the portion of the side surface exposed from the exposed portion where the heat transfer member is not in contact.

In one embodiment, a connecting portion may be provided on the side wall of each cell holder, and the connecting portions of adjacent side walls may be fitted to each other. In this case, the connecting portions of the adjacent side walls are fitted to each other, so that the airtightness between the adjacent side walls is enhanced. Therefore, it is possible to prevent substances that cause contamination from entering the space between the side surface and the fixed surface defined by the exposed portion from between the adjacent side walls. Therefore, since it is possible to suppress an increase in the insulation distance L due to an increase in the degree of contamination, it is possible to further improve the reliability of the insulation between the battery cell and the housing.

In one embodiment, at least a portion of the heat transfer member may be separated from the side wall. According to this configuration, a gap is formed between the heat transfer member and the side wall, so that when the battery module is fixed to the housing, the heat transfer member is crushed and between the exposed portion and the side wall and the fixed surface. The protrusion is more reliably suppressed. Therefore, when the battery module is fixed to the housing, it is possible to prevent the load from being applied to the battery module.

In one embodiment, the heat transfer members may be arranged at both ends of the exposed portion in the direction orthogonal to the side surface and the direction intersecting the arrangement direction, respectively, and may fill the space between the contact portion of the adjacent side wall and the space. In this case, the heat transfer member fills the space between the contact portion of the adjacent side wall and the space, so that the airtightness of the contact portion of the adjacent side wall is enhanced. This makes it possible to prevent substances that cause contamination from entering the space between the side surface and the fixed surface defined by the exposed portion from the contact portion. Therefore, it is possible to further improve the reliability of the insulation between the battery cell and the housing.

In one embodiment, the exposed portion may be provided at the center of the side wall when viewed from a direction orthogonal to the side surface. According to this configuration, the exposed portion is separated from the adjacent side walls, so that the substance causing contamination is separated from the adjacent side walls between the side surface defined by the exposed portion and the fixed surface. It is possible to suppress invasion into the space. Therefore, it is possible to further improve the reliability of the insulation between the battery cell and the housing.

In one embodiment, the battery module is arranged so as to sandwich the array, a pair of constraining members that apply a constraining load in the array direction, and elasticity arranged between the constraining member and the array and constrained together with the array. A member may be further provided. According to this configuration, for example, when the battery cell expands, the expansion of the battery cell can be absorbed by the elastic member. Therefore, it is possible to prevent the battery module from bending when the battery cell expands.

The battery pack according to one embodiment of the present invention is arranged between the above-mentioned battery module, the housing to which the battery module is fixed, and the heat transfer member and the housing, and causes friction between the heat transfer member and the housing. A friction reducing member for reducing may be provided. According to this configuration, for example, when the battery cell expands, the heat transfer member easily moves in the arrangement direction with respect to the housing. Therefore, even when the battery cell expands, deformation of the heat transfer member due to friction is suppressed, so that the area where heat is transferred between the heat transfer member and the housing can be kept constant. .. Therefore, it is possible to maintain the heat dissipation of the battery cell.

According to the present invention, there is provided a battery module and a battery pack capable of increasing the reliability of insulation between a battery cell and a housing while ensuring heat dissipation of the battery cell.

It is a perspective view which shows the battery pack which concerns on one Embodiment of this invention. It is sectional drawing which shows the battery module of FIG. It is a perspective view which shows the arrangement which constitutes the battery module of FIG. It is a perspective view which shows the cell holder. It is a partially enlarged view which shows the connection part of the cell holder of FIG. It is a figure which shows the arrangement of the heat transfer member of FIG. It is a figure which shows the modification of the arrangement of the heat transfer member of FIG. It is a perspective view which shows the modification of the cell holder of FIG. It is a perspective view which shows the further modification of the cell holder of FIG.

Hereinafter, various embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a perspective view showing a battery pack according to the present embodiment. As shown in FIG. 1, the battery pack 100 of the present embodiment includes a plurality of (for example, four) battery modules 1 and a box-shaped housing 50. The battery module 1 is housed inside the housing 50. The battery module 1 is fixed to the fixing surface 50a in the housing 50 by fixing members such as a plurality of bolts 44 (see FIG. 2). The housing 50 is made of a metal such as iron or aluminum.

FIG. 2 is a cross-sectional view showing the battery module 1 of FIG. FIG. 3 is a perspective view showing an array 3 constituting the battery module 1. In FIG. 3, the array 3 is shown in a partially decomposed state. As shown in FIGS. 2 and 3, the battery module 1 includes an array 3 in which a plurality of (for example, seven) battery cells 10 held by the cell holder 20 are arranged in a predetermined direction (arrangement direction D1). ing.

The battery cell 10 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The battery cell 10 is configured by accommodating the electrode assembly in a case into which a non-aqueous electrolyte solution is injected. The electrode assembly is a stack of a positive electrode, a negative electrode, and a separator in a predetermined order. In the present embodiment, for example, a sheet-shaped positive electrode is housed in a bag-shaped separator, and a bag-shaped separator containing a positive electrode and a sheet-shaped negative electrode are alternately laminated. The battery cell 10 has a substantially rectangular parallelepiped shape, and has an upper surface 11a, a lower surface 11b, a pair of side surfaces 11c, and a pair of surfaces 11d orthogonal to the arrangement direction D1. A pair of positive and negative electrode terminals 13 project from the upper surface 11a of the battery cell 10. The electrode terminals 13 of the adjacent battery cells 10 may be electrically connected to each other by a bus bar. As a result, the adjacent battery cells 10 are electrically connected in series.

The array 3 is constrained by the restraining member 40. The restraining member 40 is arranged so as to sandwich the array 3 in the arrangement direction D1 of the battery cell 10, and applies a restraining load to the arrangement direction D1 of the battery cell 10. In the present embodiment, the restraint member 40 has a pair of brackets 41 that sandwich the array body 3 from the arrangement direction D1, and a plurality of (for example, four) connecting members 46 that connect the pair of brackets 41 to each other. ..

The bracket 41 is formed by bending a plate-shaped member made of, for example, a metal material. A holding portion 42 and a fixing portion 43 are formed on the bracket 41 with the bent portion 41a interposed therebetween. An elastic member 30 is arranged between the holding portion 42 of one bracket 41 and the array body 3. The elastic member 30 is compressed so as to absorb the expansion of the battery cell 10, for example, when the battery cell 10 expands. The elastic member 30 is made of, for example, rubber or the like.

The sandwiching portion 42 is provided with a plurality of insertion holes 42a through which the connecting member 46 is inserted. The sandwiching portion 42 is fastened by the connecting member 46 while sandwiching the array body 3 and the elastic member 30. The connecting member 46 is a bolt 46a made of a metal such as iron. Each connecting member 46 is sequentially inserted into the insertion hole 42a of one bracket 41, the insertion holes 23b and 24b of each cell holder 20 described later, and the insertion hole 42a of the other bracket 41, and the nut 46b is inserted outside the pair of brackets 41. Is concluded by. By this fastening, a restraining load is applied to the array body 3 and the elastic member 30 in the array direction D1. The fixing portion 43 is, for example, a portion fixed to the fixing surface 50a in the housing 50 by a bolt 44.

The cell holder 20 includes two types, a cell holder 20A and a cell holder 20B. The cell holder 20A is arranged between the battery cells 10 adjacent to each other in the arrangement direction D1 and holds the battery cells 10. The cell holder 20B is arranged between the battery cells 10 arranged at both ends of the arranged battery cells 10 and the bracket 41, and holds the battery cells 10. FIG. 4 is a perspective view showing the cell holder 20A. The cell holder 20A is made of a resin material and has a partition wall 21 and a holding portion 22. The partition wall 21 has a rectangular flat plate shape extending in a direction orthogonal to (intersecting) the arrangement direction D1 of the battery cells 10. The partition wall 21 may hold a surface 11d orthogonal to the arrangement direction D1 in the battery cell 10. The holding portion 22 has a rectangular frame shape formed on the peripheral edge of the partition wall 21, and has an upper wall 23, a lower wall 24, a first side wall (side wall) 26, and a second side wall 27. The upper wall 23, the lower wall 24, the first side wall 26, and the second side wall 27 all have a flat plate shape.

The upper wall 23 faces the upper surface 11a on which the electrode terminal 13 of the battery cell 10 is formed, and may hold the upper surface 11a. The upper wall 23 projects from the upper end edge of the partition wall 21 in the arrangement direction D1 of the battery cells 10. In the present embodiment, the upper wall 23 is provided on one side 21a and the other side 21b of the partition wall 21 in the arrangement direction D1, respectively. Further, the width of the upper wall 23 in the arrangement direction D1 is smaller than, for example, half the width of the battery cell 10. A cylindrical portion 23a is provided on the upper portion of the upper wall 23. An insertion hole 23b through which the connecting member 46 is inserted is formed in the tubular portion 23a. The tubular portion 23a is formed at both ends of the upper wall 23, for example, and projects upward.

The lower wall 24 faces the lower surface 11b of the battery cell 10 and may hold the lower surface 11b. The lower wall 24 projects from the lower end edge of the partition wall 21 in the arrangement direction D1 of the battery cells 10. In the present embodiment, the lower wall 24 is provided on one side 21a and the other side 21b of the partition wall 21 in the arrangement direction D1, respectively. Further, the width of the lower wall 24 in the arrangement direction D1 is, for example, substantially half the width of the battery cell 10. That is, in a state where the battery cell 10 is held between the pair of cell holders 20, the battery cell 10 is formed by the lower wall 24 formed on one cell holder 20 and the lower wall 24 formed on the other cell holder 20. The entire lower surface 11b of the can be retained. At the lower part of the lower wall 24, a cylindrical portion 24a in which an insertion hole 24b through which the connecting member 46 is inserted is formed is provided. The tubular portion 24a is formed at both ends of the lower wall 24, for example, and projects downward.

The first side wall 26 faces the fixed surface 50a of the housing 50 and may hold one side surface 11c of the battery cell 10. The first side wall 26 is provided on one edge portion 21c on the fixed surface 50a side of the partition wall 21 and projects in the arrangement direction D1. In the present embodiment, the first side wall 26 is provided on one surface side 21a and the other surface side 21b of the partition wall 21 in the arrangement direction D1, respectively. The first side wall 26 has an exposed portion 26a that exposes a part of one side surface 11c of the battery cell 10. The exposed portion 26a is, for example, a rectangular notch-shaped portion extending in the vertical direction D2 intersecting the arrangement direction D1. In the present embodiment, the exposed portions 26a are provided on both ends of the first side wall 26 in the arrangement direction D1. The width of the first side wall 26 in the arrangement direction D1 is substantially the same as the width of the lower wall 24 at the upper end and the lower end of the first side wall 26, and is substantially half the width of the battery cell 10. The width of the first side wall 26 in the portion where the exposed portion 26a is formed is smaller than the width of the first side wall 26 at the upper end and the lower end of the first side wall 26.

The thickness N of the first side wall 26 (dimension in the direction D3 orthogonal to the arrangement direction D1 and the vertical direction D2 and facing the first side wall 26 and the fixed surface 50a) N is calculated by A × V × T / P. The insulation distance L or more and 2 mm or less proportional to the value.

In the formula (1), A is the degree of gas contamination in the space S between the one side surface 11c defined by the exposed portion 26a and the fixed surface 50a when the cell holder 20 is fixed to the fixed surface 50a. It is a coefficient that depends on. The coefficient A depending on the degree of fouling can be calculated by, for example, a known method. The degree of fouling can be classified into four grades of the degree of fouling 1 to the degree of fouling 4 specified by the standard JIS60664-1 (IEC60664-1). The degree of contamination 1 is a state in which no contamination occurs or only non-conductive contamination occurs in a dry state. The degree of fouling 2 is a state in which non-conductive contamination occurs, but it is sometimes expected that dew condensation will temporarily cause conductivity. The degree of fouling 3 is a state in which conductive contamination occurs, or dry non-conductive contamination but which becomes conductive due to expected dew condensation. The degree of fouling 4 is a state in which continuous conductivity is generated by conductive dust, rain or other wet conditions. Examples of substances that cause gas contamination in the space S include salt, water, dust, and rust. In general, the higher the grade of the degree of pollution in the space S, the larger the insulation distance L, and the lower the grade of the degree of pollution in the space S, the smaller the insulation distance L.

In equation (1), V is a coefficient depending on the voltage difference between the battery cell 10 and the housing 50. Generally, the larger the voltage difference between the battery cell 10 and the housing 50, the larger the coefficient V, and the smaller the voltage difference between the battery cell 10 and the housing 50, the smaller the coefficient V. Therefore, the larger the voltage difference between the battery cell 10 and the housing 50, the larger the insulation distance L, and the smaller the voltage difference between the battery cell 10 and the housing 50, the smaller the insulation distance L.

In equation (1), T is a coefficient that depends on the temperature in the space S. The temperature-dependent coefficient T can be calculated, for example, by a known method. Generally, the higher the temperature, the larger the coefficient T, and the lower the temperature, the smaller the coefficient T. Therefore, the higher the temperature, the larger the insulation distance L, and the lower the temperature, the smaller the insulation distance L.

In equation (1), P is a coefficient depending on the atmospheric pressure in the space S. The coefficient P depending on the atmospheric pressure can be calculated by, for example, a known method. In general, the higher the atmospheric pressure, the larger the coefficient P, and the lower the atmospheric pressure, the smaller the coefficient P. Therefore, the lower the atmospheric pressure, the larger the insulation distance L, and the higher the atmospheric pressure, the smaller the insulation distance L.

Under normal operating conditions (for example, when the voltage difference between the battery cell 10 and the housing 50 is about 300 V, the temperature is about 60 ° C to 80 ° C, and the atmospheric pressure is about 50 kPa to 100 kPa). The insulation distance L is, for example, less than 1 mm. Therefore, by setting the thickness of the first side wall 26 to 1 mm or more, it is possible to secure a distance of an insulation distance L or more between one side surface 11c of the battery cell 10 and the fixed surface 50a.

As shown in FIG. 2, in a state where one battery cell 10 is held by a pair of cell holders 20, the exposed portion 26a of one side 21a of the partition wall 21 and the other cell holder 20 of one cell holder 20. The exposed portion 26a of the other surface side 21b of the partition wall 21 is integrated. A part of one side surface 11c of the battery cell 10 held by the pair of cell holders 20 is exposed from the integrated exposed portion 26a. The portion of the side surface 11c of the battery cell 10 that is not exposed from the exposed portion 26a is in contact with the first side wall 26.

A connecting portion 28 is provided on the first side wall 26 of each cell holder 20. The connecting portions 28 of the other adjacent first side walls 26 are fitted to each other (see FIG. 5). The connecting portions 28 are provided at both ends of the first side wall 26 in the arrangement direction D1. Further, the connecting portion 28 is provided at the upper end and the lower end (that is, a portion other than the exposed portion 26a) of the first side wall 26 in the vertical direction D2. In the present embodiment, the connecting portion 28 has a convex portion 28a formed at one end of the first side wall 26 in the arrangement direction D1 and a concave portion 28b formed at the other end of the first side wall 26 in the arrangement direction D1. include. The convex portion 28a of the connecting portion 28 provided on one first side wall 26 fits into the concave portion 28b of the connecting portion 28 provided on the other adjacent first side wall 26 on the one end side. On the other hand, the concave portion 28a of the connecting portion 28 provided on the other first side wall 26 adjacent to the concave portion 28b of the connecting portion 28 provided on the first side wall 26 is fitted with the convex portion 28a of the connecting portion 28 provided on the other first side wall 26. As described above, the connecting portion 28 has a so-called inlay structure.

The second side wall 27 is located on the opposite side of the first side wall 26 in direction D3 and may hold the other side surface 11c of the battery cell 10. The second side wall 27 is provided on the other edge portion 21d of the partition wall 21 and projects in the arrangement direction D1. In the present embodiment, the second side wall 27 is provided on one side 21a and the other side 21b of the partition 21 in the arrangement direction D1, respectively. The width of the second side wall 27 in the arrangement direction D1 is substantially the same as the width of the lower wall 24, and is substantially half the width of the battery cell 10. In a state where the battery cell 10 is held between the pair of cell holders 20, the second side wall 27 of one cell holder 20 and the second side wall 27 of the other cell holder 20 cause the other side surface 11c of the battery cell 10 to be formed. The whole can be retained.

As shown in FIGS. 2 and 6, the battery module 1 includes a TIM (Thermal Interface Material) as a heat transfer member 7. The heat transfer member 7 has an insulating property and can transfer heat between one side surface 11c and the fixed surface 50a. The heat transfer member 7 is fixed to a part of one side surface 11c. When the battery module 1 is fixed to the fixed surface 50a, the heat transfer member 7 is in a state of being arranged between one side surface 11c of the battery cell 10 and the fixed surface 50a. That is, one side surface 11c of the battery cell 10 comes into contact with the fixed surface 50a via the heat transfer member 7. The heat transfer member 7 is in contact with a part of one side surface 11c exposed from the exposed portion 26a. In the present embodiment, the heat transfer member 7 is arranged apart from the edge portion (that is, the first side wall 26) of the exposed portion 26a. That is, a gap (space S) is formed between the heat transfer member 7 and the first side wall 26. By arranging the heat transfer member 7 in this way, the non-contact portion 11e exposed from the exposed portion 26a and not in contact with the heat transfer member 7 is formed so as to surround the heat transfer member 7. When the heat transfer member 7 is arranged in this way, the space S is a space formed between the non-contact portion 11e and the fixed surface 50a. The heat transfer member 7 is, for example, a long elastic sheet having elasticity, and is made of silicon rubber, acrylic rubber, or the like.

A slip sheet 8 (friction reducing member) for reducing friction between the heat transfer member 7 and the housing 50 is arranged between the heat transfer member 7 and the fixed surface 50a of the housing 50. The slip sheet 8 is in close contact with, for example, the heat transfer member 7 so that the heat transfer member 7 can be easily moved in the arrangement direction D1 with respect to the housing 50. The slip sheet 8 is made of a resin material having heat conductivity such as polyethylene terephthalate (PET) and having a small coefficient of friction.

As described above, in the battery module 1, a heat transfer member 7 capable of transferring heat is fixed to a part of the exposed one side surface 11c between the one side surface 11c and the fixed surface 50a (FIG. 2). reference). As a result, the heat generated in the battery cell 10 can be efficiently transferred to the housing 50, so that the heat dissipation of the battery cell 10 can be ensured. Further, in the above battery module 1, the thickness N of the first side wall 26 of the cell holder 20 is an insulation distance L or more proportional to the value calculated by A × V × T / P. As a result, a distance of an insulation distance L or more is secured between one side surface 11c of the battery cell 10 and the fixed surface 50a of the housing 50. Therefore, of the one side surface 11c exposed from the exposed portion 26a, even in the portion where the heat transfer member 7 is not in contact (non-contact portion 11e (see FIG. 6)), the battery cell 10 and the housing 50 are insulated from each other. It is possible to increase reliability. Further, by reducing the thickness of the first side wall 26 to 2 mm or less, the thickness of the first side wall 26 can be reduced. As a result, when the battery module 1 is fixed to the fixed surface 50a, the thickness of the heat transfer member 7 arranged between the one side surface 11c and the fixed surface 50a is also 2 mm or less. In this way, since the thickness of the heat transfer member 7 is reduced, the heat generated in the battery cell 10 can be efficiently transferred to the housing 50. Further, even in the portion of the first side wall 26 other than the exposed portion 26a, the heat generated in the battery cell 10 can be efficiently transferred to the housing 50 via the first side wall 26. Therefore, the heat dissipation of the battery cell 10 can be improved.

Further, when the battery module 1 is fixed to the housing 50, the space S functions as a gap that serves as an escape place for the heat transfer member 7. Therefore, it is possible to prevent the heat transfer member 7 from being crushed and protruding from the exposed portion 26a between the first side wall 26 and the fixed surface 50a.

The thickness of the first side wall 26 is 1 mm or more. By setting the thickness of the first side wall 26 to 1 mm or more in this way, the distance between one side surface 11c of the battery cell 10 and the fixed surface 50a of the housing 50 can be set to the insulation distance L or more. Therefore, it is possible to improve the reliability of the insulation between the battery cell 10 and the housing 50 even in the non-contact portion 11e of the one side surface 11c exposed from the exposed portion 26a to which the heat transfer member 7 is not in contact. be.

Further, as shown in FIG. 6, at least a part of the heat transfer member 7 is separated from the first side wall 26. As a result, a gap is formed between the heat transfer member 7 and the first side wall 26. Therefore, when the battery module 1 is fixed to the housing 50, the heat transfer member 7 is crushed and the first from the exposed portion 26a. The protrusion between the side wall 26 and the fixed surface 50a is more reliably suppressed. Therefore, when the battery module 1 is fixed to the housing 50, it is possible to prevent the load from being applied to the battery module 1.

Further, as shown in FIG. 5, a connecting portion 28 is provided on the first side wall 26 of each cell holder 20, and the connecting portions 28 of the adjacent first side walls 26 are fitted to each other. As a result, the connecting portions 28 of the adjacent first side walls 26 are fitted to each other, so that the airtightness between the adjacent first side walls 26 is enhanced. Therefore, it is possible to prevent a substance that causes contamination from entering the space S between the one side surface 11c and the fixed surface 50a defined by the exposed portion 26a from between the adjacent first side walls 26. Therefore, since it is possible to suppress an increase in the insulation distance L due to an increase in the degree of contamination, it is possible to further improve the reliability of the insulation between the battery cell 10 and the housing 50.

Further, as shown in FIG. 2, the battery module 1 is arranged so as to sandwich the array body 3, and includes a pair of restraint members 40 that apply a restraint load in the array direction D1, and the restraint members 40 and the array body 3. It is provided with an elastic member 30 arranged between them and constrained together with the array 3. Thereby, for example, when the battery cell 10 expands, the expansion of the battery cell 10 can be absorbed by the elastic member 30. Therefore, it is possible to prevent the battery module 1 from bending when the battery cell 10 expands.

Further, as shown in FIG. 1, the battery pack 100 is arranged between the above-mentioned battery module 1, the housing 50 to which the battery module 1 is fixed, and the heat transfer member 7 and the housing 50, and conducts heat transfer. A slip sheet 8 for reducing friction between the heat member 7 and the housing 50 is provided. This makes it easier for the heat transfer member 7 to move in the arrangement direction D1 with respect to the housing 50, for example, when the battery cell 10 expands. Therefore, even when the battery cell 10 expands, deformation of the heat transfer member 7 due to friction is suppressed, so that the area where heat is transferred between the heat transfer member 7 and the housing 50 is kept constant. Can be kept. Therefore, it is possible to maintain the heat dissipation of the battery cell 10.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

For example, in the above embodiment, the heat transfer member 7 is arranged apart from the edge portion of the exposed portion 26a, but the arrangement of the heat transfer member 7 can be appropriately changed. FIG. 7 is a diagram showing a modified example of the arrangement of the heat transfer member 7. As shown in FIG. 7, at least a part of the heat transfer member 7 is separated from the first side wall 26. The heat transfer members 7 are arranged at both ends of the exposed portion 26a in the vertical direction D2, and fill the space between the contact portion of the adjacent first side wall 26 and the space S. The non-contact portion 11e and the space S are formed in the central portion of the exposed portion 26a in the vertical direction D2. In this case, the heat transfer member 7 fills the space between the contact portion of the adjacent first side wall 26 and the space S, so that the airtightness of the contact portion of the adjacent first side wall 26 is enhanced. As a result, the substance causing contamination can be prevented from entering the space S between the one side surface 11c and the fixed surface 50a defined by the exposed portion 26a from the contact portion. Can be suppressed. Therefore, it is possible to further improve the reliability of the insulation between the battery cell 10 and the housing 50.

Further, the cell holder 20 may have an exposed portion 26a and may have another shape. FIG. 8 is a diagram showing a modified example of the cell holder 20. As shown in FIG. 8, the cell holder 120 includes a partition wall 121, an upper wall 123, a lower wall 124, a first side wall 126, a second side wall 127, and an exposed portion 126a formed on the first side wall 126. Have. The thickness N of the first side wall 126 is an insulation distance L or more (or 1 mm or more) and 2 mm or less. The cell holder 120 is different from the cell holder 20 of the above embodiment in that the upper wall 123, the lower wall 124, the first side wall 126, and the second side wall 127 project only to one surface side 121a of the partition wall 121 in the arrangement direction D1. is doing. In this case, the widths of the upper wall 123, the lower wall 124, the first side wall 126, and the second side wall 127 in the arrangement direction D1 are substantially the same as the width of the battery cell 10. Further, the exposed portion 126a is formed only on one surface side 121a of the partition wall 121. Even in the battery module having such a cell holder 120, since the thickness of the first side wall 126 is the insulation distance L or more (or 1 mm or more) and 2 mm or less, the same effect as that of the battery module 1 of the above embodiment can be obtained. Can be done.

FIG. 9 is a diagram showing a further modification example of the cell holder 20. As shown in FIG. 9, the cell holder 220 includes a partition wall 221, an upper wall 223, a lower wall 224, a first side wall 226, a second side wall 227, and an exposed portion 226a formed on the first side wall 226. Have. The thickness N of the first side wall 226 is an insulation distance L or more (or 1 mm or more) and 2 mm or less. The upper wall 223, the lower wall 224, the first side wall 226, and the second side wall 227 project only to one side 121a of the partition wall 121 in the arrangement direction D1 like the cell holder 120. The difference between the cell holder 220 and the cell holder 120 is that the exposed portion 226a is provided in a window shape at the central portion of the first side wall 226 when viewed from the direction D3. According to this configuration, since the exposed portion 226a is separated from the adjacent first side wall 226, the substance causing contamination is formed by the exposed portion 226a from between the adjacent first side walls 226. It is possible to suppress the invasion into the space S between the side surface 11c and the housing 50. Therefore, it is possible to further improve the reliability of the insulation between the battery cell 10 and the housing 50.

Further, the thicknesses of the partition wall 21, the upper wall 23, the lower wall 24, and the second side wall 27 can be arbitrarily set. For example, the thicknesses of the partition wall 21, the upper wall 23, the lower wall 24, and the second side wall 27 may be substantially the same as or different from the thickness N of the first side wall 26.

Further, in the above embodiment, the connecting portion 28 is provided only on the first side wall 26, but the connecting portion 28 may also be provided on the upper wall 23, the lower wall 24, and the second side wall 27. Further, the configuration of the connecting portion 28 is not limited to the above embodiment and can be changed as appropriate. The connecting portion 28 may not be provided on the first side wall 26.

Further, in the above embodiment, the example in which the elastic member 30 is arranged between the array body 3 and the restraint member 40 has been described, but the battery module 1 does not have to have the elastic member 30.

Further, in the above embodiment, the example in which the slip sheet 8 is arranged between the heat transfer member 7 and the housing 50 has been described, but the battery pack 100 does not have to have the slip sheet 8. Further, the slip sheet 8 may also be arranged between the first side wall 26 and the housing 50. In this case, the slip sheet 8 between the heat transfer member 7 and the housing 50 and the slip sheet 8 between the first side wall 26 and the housing 50 may be integrated. That is, one slip sheet 8 may be arranged between the battery module 1 and the housing 50 so as to cover the entire surface of the battery module 1 facing the housing 50.

1 ... Battery module, 3 ... Arrangement, 7 ... Heat transfer member, 8 ... Slip sheet (friction reduction member), 10 ... Battery cell, 11c ... Side surface, 20, 120, 220 ... Cell holder, 21 ... Bulk partition, 21c ... 1 Edge, 22 ... Holding, 26, 126, 226 ... First side wall (side wall), 26a, 126a, 226a ... Exposed, 28 ... Connecting, 30 ... Elastic member, 40 ... Restraining member, 50 ... Housing, 50a ... Fixed surface, 100 ... Battery pack, D1 ... Arrangement direction, D2 ... Vertical direction, D3 ... Direction, L ... Insulation distance, N ... Thickness, S ... Space.

Claims (8)

A battery module in which a plurality of battery cells held by a cell holder are arranged in a predetermined direction and are fixed to a fixed surface in a housing.
The cell holder is
A partition wall that holds a plane orthogonal to the arrangement direction in the battery cell,
It has a holding portion provided on one edge of the partition wall, including a side wall facing the fixed surface and holding a side surface of the battery cell.
The side wall has an exposed portion that exposes a part of the side surface of the battery cell.
A heat transfer member having insulating properties and capable of transferring heat between the side surface and the fixed surface is fixed to a part of the side surface exposed in the exposed portion.
The thickness of the side wall is an insulation distance L or more and 2 mm or less specified in JIS standards .
When the cell holder is fixed to the fixed surface, the space between the side surface and the fixed surface defined by the exposed portion exposes a part of the side surface for each of the plurality of battery cells. In addition, a plurality of batteries are arranged in the above-mentioned arrangement direction.
The heat transfer member is a battery module arranged in each of the plurality of spaces and provided for each of the plurality of battery cells. The battery module according to claim 1, wherein the thickness of the side wall is 1 mm or more. A connection portion is provided on the side wall of each cell holder.
The battery module according to claim 1 or 2, wherein the connecting portions of the adjacent side walls are fitted to each other. The battery module according to any one of claims 1 to 3, wherein at least a part of the heat transfer member is separated from the side wall. The heat transfer member is arranged at both ends of the exposed portion in a direction orthogonal to the side surface and a direction intersecting the arrangement direction, and fills a space between the contact portion of the adjacent side wall and the space. Item 5. The battery module according to any one of Items 1 to 4. The battery module according to any one of claims 1 to 4, wherein the exposed portion is provided in the central portion of the side wall when viewed from a direction orthogonal to the side surface. A pair of constraint members arranged so as to sandwich the array and applying a constraint load in the array direction,
The battery module according to any one of claims 1 to 6, further comprising an elastic member arranged between the restraining member and the array and constrained together with the array. The battery module according to any one of claims 1 to 7.
The housing to which the battery module is fixed and the housing
A battery pack comprising a friction reducing member arranged between the heat transfer member and the housing and reducing friction between the heat transfer member and the housing.

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